1. Field of the Invention
The present invention relates to an ink-jet recording head where recording liquid usually called xe2x80x9cinkxe2x80x9d is ejected in the form of tiny liquid droplets from fine ejection ports, and is flown into the atmosphere and deposited on a medium to be recorded, and also relates to its manufacturing method.
2. Brief Description of the Related Art
An ink-jet recording head employed in the above-mentioned ink-jet recording method, has usually fine ejection ports (orifices), ink flow paths and energy generating modules for ejecting liquid arranged on portions of the ink flow paths. Manufacturing procedures described, for example, in the U.S. Pat. Nos. 4,657,631 and 5,030,317 etc. have been known as manufacturing methods of the above-mentioned conventional ink-jet recording heads
In order to obtain images of high quality by employing these ink-jet recording heads, it is desirable to keep the volume and ejecting velocity of ejected recording liquid droplets as uniform as possible.
For attaining such high quality the U.S. Pat. No. 6,155,673, for example, discloses ink-jet recording heads where driving signals in response to information to be recorded are applied to ink ejecting pressure generating elements (electro-thermal conversion modules), for generating enough thermal energy to raise the ink temperature over a nucleus boiling point so as to form bubbles, which drive ink droplets flying into the atmosphere.
In the above-mentioned ink-jet recording heads, the shorter is a distance between the electro-thermal conversion module and the orifice (hereinafter referred as xe2x80x9cOH distancexe2x80x9d) the more preferable it is. Since the OH distance virtually determines the ejected volume, it is necessary to set the OH distance precisely with good reproducibility.
The above-mentioned manufacturing method of the ink-jet recording head with the short OH distance and high accuracy is disclosed for example, in the U.S. Pat. No. 5,478,606. Hereinafter the outline of the manufacturing method is explained.
The manufacturing method in the above-mentioned laid open patent is characterized by the following steps comprising a step to form an ink-flow pattern out of a soluble resin on a base plate, a step to form a coated resin layer, which forms walls of ink-flow on the above-mentioned soluble resin layer coated with a resin solution including a solid epoxy resin at the ordinary temperature, a step to form ejection ports on the resin coated layer over the above-mentioned ejecting pressure generating elements and a step to dissolve the soluble resin layer.
The finished recording head is obtained after a water-repellent agent coated on a flexible material such as silicon rubber etc. is transferred to a surface of the ink-jet recording head where ejection ports are formed in the above-mentioned way, dried and cured.
Ejecting (flying) directions of ink droplets ejected from ejection ports in the ink-jet recording head manufactured by the above-mentioned method deviate when liquid for recording such as ink is accumulated around the ejection ports so that recording results of high quality can no longer be attained any more. As measures against such deviations, a method of water-repellent treatment on a surface where ejection ports are formed, to prevent the liquid accumulation that cause the deviations of the ejecting directions, around ejection ports has been known.
Even if the above-mentioned water-repellent treatment is carried out, sometimes ink accumulated around the ejection ports moves toward the ejection ports and clogs the ejection ports. Measures to prevent a large amount of ink from moving toward the ejection ports is attained by forming ink deposition areas where a hydrophilic treatment is carried out at portions spaced slightly apart from the ejection ports (hereinafter referred as xe2x80x9cpartial hydrophilic treatmentxe2x80x9d).
As the above-mentioned partial hydrophilic treatment, the hydrophilic treatment zones are formed by fusing and evaporating a coated resin layer formed out of dissolved florine resin with an abrasion treatment by employing an exima laser etc. However the method requires an expensive apparatus and a complicated procedure so that the manufacturing cost for such ink-jet head becomes more expensive.
The objective of the present invention is to provide a partially hydrophilic treatment on an ink-jet recording head bearing enough toughness against outside factors such as a recording sheet jam and abrasion caused by paper dust, carried out by a simple procedure at a low cost.
In order to attain the objective, the present invention provides either one of the methods or the ink-jet recording head according to the following ways (1) to (5).
(1) A manufacturing method of an ink-jet recording head including ejection ports constituted by a resin layer and a water-repellent photosensitive resin layer, both resins are curable by irradiating with an energy active ray, comprising steps of:
preparing a substrate having ink ejecting energy generating portions, forming the resin layer on the substrate,
curing the resin layer except portions for the ejection ports and the periphery of the ejection ports by irradiating with the energy active ray,
forming the water-repellent photosensitive resin layer on the cured resin layer,
curing the water-repellent photosensitive resin layer and non irradiated portions of the resin layer except portions for the ejection ports simultaneously by irradiating with the energy active ray,
forming the ejection ports by developing the resin layer anal the water-repellent photosensitive resin layer.
(2) A manufacturing method of the ink-jet recording head according to (1) wherein energy generating portions are made of electro-thermal energy conversion modules which generate thermal energy.
(3) A manufacturing method of the ink-jet recording method according to (1) wherein the ink-jet head is a full-line type ink-jet recording head where a plurality of the ejection ports are formed to cover a whole width of a recording medium.
(4) A manufacturing method of the ink-jet recording head according to (1) wherein ejection ports for multicolor recording are formed in one piece.
(5) An ink-jet recording head manufactured by either one of the methods of (1) to (4), An ink-jet recording head with no temporal interruptions of ink ejection, with stable recording images of high quality, and with virtually no deviations in ink ejecting directions is obtained at a low cost, when the above-mentioned surface treating method according to the present invention is employed.